Heat exchanger arrangement

ABSTRACT

A water tube boiler having a first section whose tubes define a upright combustion chamber and a second section bounding a horizontal passage for the combustion gases are connected to a horizontally elongated drum mounted on the frame of the first section. Differential thermal expansion and contraction of the two sections, which are mounted on a common, rigid support, such as the concrete floor of a boiler house, is made possible by flexible connecting conduits between the second section and the drum.

United States Patent 1191 ATP Stiigmiiller Dec. 23, 1975 HEAT EXCHANGER ARRANGEMENT 2,290,882 7/1942 Keenan, Jr 122/421 2,515,443 7/1950 Ebbets [22/510 [75] Invent stogmuller crefensee 3,280,800 10/1966 Sullivan 122/510 Zandbuel, Sw1tzerland [73] Assignee: Heinrich Vorkauf, Berlin, Germany Primary Examiner-Wende l E. Burns Assistant Examiner-Theophil W. Streule, Jr. [22] Ffled' 1975 Attorney, Agent, or FirmHans Berman [21] Appl. No.: 546,421

[57] ABSTRACT [30] Foreign Application Priority Data A water tube boiler having a first section whose tubes Feb. 1,1974 Germany 7403348 define a p Combustion ha and a Second section bounding'a horizontal passage for the combus- [52] US. Cl. 165/82; 122/510 IiOn gases e nnected to a horizontally elongated [51] Int. Cl. F28F 5/00 m mounted on he frame of h first section- Dif- [58] Field of Search 165/81, 82; [22/467, 235C, ferential thermal expansion and contraction of the two 122/510, 421 sections, which are mounted on a common, rigid sup- I I port, such as the concrete floor of a boiler house, is [56] References Cited made possible by flexible connecting conduits be- UNTTEDVSTATES PATENTS tween the second section and the drum. 2,285,651 6/1942 Fischer 165/82 6*Claims, 2 Drawing Figures 1 5 1 n A 16 ,11 v 1 r ,13 ,131 12 I 7 t l B-- I k P i P 1 1 1 1 n 1 1 15 1 1 1 15 11. 1s 111111 1 1,; 2 11 1 I 1 1/1/11 ll Hr US. Patent Dec. 23, 1975 3,927,714

3% W!!! W l 1. 'MIHUIIIIIHIYIHII" HEAT EXCHANGER ARRANGEMENT This invention relates to heat exchangers, and particularly to a heat exchanger having two sections arranged on different levels and connected to a common collector vessel.

In its more specific aspects, the invention will be described hereinbelow with reference to a water tube boiler of the type in which one section has tubes whose outer faces bound a combustion chamber and a second section has heat exchange elements which bound a horizontal passage for the combustion products from the combustion, chamber to a flue or stack.

Such an arrangement is known, for example, from the German Pat.-No. 767,876. The heat exchangeor evaporator elements of the second section are suspended from above in a horizontal duct and are free to expand in a downward direction. In other water tube boilers, all heat exchange tubes and a collector vessel are mounted on vertical return pipes supported on the ground or floor, beneath the boiler.

The two types of boilers briefly described above are free from significant problems resulting from differential thermal expansion of heat exchanger sections. Differential thermal expansion and contraction presents difficult problems in a boiler in which the several sections need to be supported on vertically spaced portions of a support, as in a boiler having a vertically elongated combustion chamber whose top communicates with a horizontal passage for combustion gases lined with heatexchange elements. M

It is a primary object of this invention to provide a heat exchanger arrangement capable of coping successfully with differential thermal expansionand contraction of its sections.

In its more specific aspects, the invention provides a heat exchanger arrangement in which a first and a second heat exchanger section are mounted on respective vertically spaced portions of a support. The first section has an upright frame mounted on the lower support portion and includes a plurality of heat exchange tubes supported on the frame. Respective outer faces of the tubes jointly define a first part of a passage for a fluid heating medium. The second section, mounted on the higher support portion, includes a plurality of hollow heat exchange elements whose respective outer faces jointly define a second part of the afore-mentioned passage for flow of the heating medium through the second section in a predetermined direction. A horizontally elongated collector vessel is mounted on the frame of the first section and is connected by first conduits with the tubes of the first section, and by yieldably resilient second conduits with the heat exchange elements of the second section. The flexibility of the second conduits is sufficient to permit differential thermal expansionand contraction of the two sections without stressing these sections.

Other features, additional objects, and many of the attendant advantages of this invention will readily be appreciated as the same becomes better understood by reference to the following detailed description of a preferred embodiment when considered in connection with the appended drawing in which:

FIG. 1 shows a water-tube boiler of the invention in fragmentary side elevation; and

FIG. 2 shows the apparatus of FIG. 1 in top plan view.

The drawing shows only as much of an otherwise conventional water-tube boiler as is needed for an understanding of the invention. More specifically, the boiler shell and an oil burner have been omitted, and the conduits supplying feed water to the boiler and transferring the generated steam to an engine have not been shown since they are conventional and not directly relevant to this invention.

The invention is more specifically concerned with the heat exchanging devices of the boiler and their connections. The illustrated boiler has two heat exchanger sections 1, 2. The vertical water tubes 3 of the first section arejoined at their lower ends to manifolds 4 and at their upper ends to headers 5 which, in turn, are connected by pipes 5 to a generally cylindrical drum 6, a collector vessel, whose longitudinal axis is horizontal.

The drum 6 ismounted on the top of a frame constituted by vertical down pipes 7 and return pipes 8 which are connected by the manifolds 4 and headers 5 and carry the heat exchange tubes 3. The frame rests on engagement elements 9, 9, 10 on the concrete floor of the boiler house, not otherwise shown, which supports the boiler. i

The outer faces of the tubes 3 define a first, vertical part of a passage for a heating medium indicated in FIG. 1 by arrows P and mainly consisting of combustion products emitted by the non-illustrated, conventional oil burner and hot excess air. The second, horizontal part of the passage is bounded by the second section 2 of the heat exchanger, and more specifically by external faces of hollow heat exchange elements 13 which may be tubes, hollow plates, or the like, and each extend between lower distribution pipes 11 and upper headers or collecting tubes 12.

The section 2 rests on engagement elements l4, 14, 15 on an integral, raised platform of the boiler house floor. Resiliently flexible conduits 16, 17 respectively connect the pipes 11 and headers 12 to the drum 6. As

i is shown in FIG. 2, the boiler, as far as illustrated, is

approximately symmetrical relative to a vertical meaxis of the drum 6. As is shown specifically for the conduits 17 in FIG. 2, each of the conduits l6, 17 has one end communicating with the elements 13 through a pipe 1 l or header l2 and another end communicating with one of two axial end portions of the drum 6 which are divided by the plane E. An intermediate portion of each conduit l6, 17 is angularly offset from the two ends and approximately perpendicular to the plane E, thereby giving sufficient flexibility to the connection between the heat exchanger section 2 and the drum 6 to compensate for the differcnccs in thermal expansion and contraction between the two sections 1 and 2 without jeopardizing the structural integrity of the heat exchange arrangement.

The frame of the first section 1 engages the boiler house floor in four points. The support 9 under the downpipe 7 seen in FIG. 1 holds the pipe in a fixed horizontal position. Rollers are mounted under the other upright members of the frame as shown at 10 in FIG. 1 and not explicitly visible at 9 so that horizontal expansion or contraction of the framedoes not induce any significant stresses in the structure. Similarly, only the support 14 on the boiler house platform fixedly engages the heat exchange unit 2. The supports indicated at 14 and 15 are equipped with rollers permitting movement toward and away from the fixed support 14.

Because of the afore-described shape of the conduits l6, 17, the two heat exchanger section 1, 2 can be juxtaposed very closely, yet move relative to each other, thereby flexing the conduits l6, 17. As is evident particularly from FIG. 2, the spacing of the supports 9, 9 of the group supporting the first section 1 from the closest supports 14, 14 of the group supporting the second section 2 in the direction of gas flow through the section 2 is but a small fraction of the transverse dimension of the gas passage in the second section.

While the invention has been described with reference to a water-tube steam boiler, it finds a useful field of application in any sectionalized heat exchanger arrangement in which the several sections are mounted on different levels of practically rigid supporting structure or otherwise arranged in such a manner as to exhibit different dimensional changes under thermal load. It should be understood, therefore, that the foregoing disclosure relates only to a preferred embodiment of the invention, and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purpose of the disclosure which do not constitute departures from the spirit and scope of the invention set forth in the appended claims.

What is claimed is: 1. A heat exchanger arrangement comprising: a. a support having two vertically spaced portions; b. a first heat exchanger section including 1. an upright frame mounted on the lower one of said portions, and

2. a plurality of heat exchange tubes supported on said frame, respective outer faces of said tubes jointly defining a first part of a passage for a fluid heating medium;

c. a second heat exchanger section mounted on the higher one of said portions and including a plurality of hollow heat exchange elements having respective outer faces jointly defining a second part of said passage for flow of said medium through said second section in a predetermined direction;

d. a horizontally elongated collector vesselmounted on said frame;

e. a plurality of first conduits connecting said tubes to said vessel; and

f. a plurality of second, yieldably resilient conduits connecting said elements to said vessel to permit differential thermal expansion and contraction of said sections.

2. An arrangement as set forth in claim 1, wherein said collector vessel has a longitudinal axis, and an upright median plane transverse to said axis, and said second conduits include two collecting tubes elongated in said direction, said collecting tubes being transversely spaced from each other in a horizontal direction and located on opposite sides of said median plane, and two connecting tubes respectively connecting said collecting tubes to longitudinally terminal portions of said collector vessel on the far side of said median plane.

3. An arrangement as set forth in claim 1, wherein said sections engage respective groups of engagement portions of said support, said groups being spaced from each other in said predetermined direction, the spacing of the respective closest members of said groups being smaller than any dimension of said second part perpendicular to said predetermined direction.

4. An arrangement as set forth in claim 1, wherein said collector vessel has a longitudinal axis and a median plane perpendicular to said axis, said parts of said passage being parallel to said plane and offset angulary from each other.

5. An arrangement as set forth in claim 4, wherein each of said second conduits is elongated and has two longitudinally terminal portions communicating with said collector vessel and with one of said elements respectively on opposite sides of said median plane.

6. An arrangement as set forth in claim 5, wherein each of said second conduits has a portion longitudinally intermediate said terminal portions and angularly offset from each terminal portion, said intermediate portion being approximately perpendicular to said median plane. 

1. A heat exchanger arrangement comprising: a. a support having two vertically spaced portions; b. a first heat exchanger section including
 1. an upright frame mounted on the lower one of said portions, and
 2. a plurality of heat exchange tubes supported on said frame, respective outer faces of said tubes jointly defining a first part of a passage for a fluid heating medium; c. a second heat exchanger section mounted on the higher one of said portions and including a plurality of hollow heat exchange elements having respective outer faces jointly defining a second part of said passage for flow of said medium through said second section in a predetermined direction; d. a horizontally elongated collector vessel mounted on said frame; e. a plurality of first conduits connecting said tubes to said vessel; and f. a plurality of second, yieldably resilient conduits connecting said elements to said vessel to permit differential thermal expansion and contraction of said sections.
 2. a plurality of heat exchange tubes supported on said frame, respective outer faces of said tubes jointly defining a first part of a passage for a fluid heating medium; c. a second heat exchanger section mounted on the higher one of said portions and including a plurality of hollow heat exchange elements having respective outer faces jointly defining a second part of said passage for flow of said medium through said second section in a predetermined direction; d. a horizontally elongated collector vessel mounted on said frame; e. a plurality of first conduits connecting said tubes to said vessel; and f. a plurality of second, yieldably resilient conduits connecting said elements to said vessel to permit differential thermal expansion and contraction of said sections.
 2. An arrangement as set forth in claim 1, wherein said collector vessel has a longitudinal axis, and an upright median plane transverse to said axis, and said second conduits include two collecting tubes elongated in said direction, said collecting tubes being transversely spaced from each other in a horizontal direction and located on opposite sides of said median plane, and two connecting tubes respectively connecting said collecting tubes to longitudinally terminal portions of said collector vessel on the far side of said median plane.
 3. An arrangement as set forth in claim 1, wherein said sections engage respective groups of engagement portions of said support, said groups being spaced from each other in said predetermined direction, the spacing of the respective closest members of said groups being smaller than any dimension of said second part perpendicular to said predetermined direction.
 4. An arrangement as set forth in claim 1, wherein said collector vessel has a longitudinal axis and a median plane perpendicular to said axis, said parts of said passage being parallel to said plane and offset angulary from each other.
 5. An arrangement as set forth in claim 4, wherein each of said second conduits is elongated and has two longitudinally terminal portions communicating with said collector vessel and with one of said elements respectively on opposite sides of said median plane.
 6. An arrangement as set forth in claim 5, wherein each of said second conduits has a portion longitudinally intermediate said terminal portions and angularly offset from each terminal portion, said intermediate portion being approximately perpendicular to said median plane. 